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This car might look insane, but it's actually a sign that Rolls-Royce is working on something even more insane: an SUV.

Is it the latest example of Hollywood excess? Some hot rodder's bizarre fantasy?

It's neither. That jacked-up, bewinged Rolls-Royce you see in the photo above is actually a rolling testbed for something that is arguably even wackier: the first-ever Rolls-Royce SUV.

That's an official Rolls-Royce photo. Is it proof Rolls has gone off the deep end?

Yes, Rolls-Royce is developing an SUV Luxury SUVs are nothing new, of course, and it's not news that the segment has been booming in the last few years. Premium brands such as Porsche and BMW (NASDAQOTH:BAMXF) have profited greatly from "crossover" SUVs that combine some off-road capability with car-like handling.

But it was still a surprise when Rolls-Royce, the 111-year-old maker of stately sedans for very well-heeled clients, announced in February that it is "developing an all-new Rolls-Royce with exceptional presence, elegance and purpose:

• A car that offers the luxury of a Rolls-Royce in a vehicle that can cross any terrain

It's an SUV, in other words, even if Rolls-Royce would rather describe it delicately as a "high-bodied car" that can "cross any terrain." And the car in the photo above is what Rolls calls an "engineering mule," a test bed for the all-wheel-drive system and other technologies that will go into the future Rolls SUV.

But why does Rolls-Royce -- Rolls-Royce! -- want an SUV?

It's about profits, and something elseRolls-Royce said, "many discerning customers have urged us to develop this new car -- and we have listened."

That is no doubt true. But it's also true that Rolls' corporate parent, BMW, knows full well that there's an opportunity for an ultra-luxury SUV right now -- and that if Rolls doesn't seize it, its rivals will.

Specifically, the Bentley brand, now owned by BMW rival Volkswagen Group (NASDAQOTH:VWAGY), is expected later this year to unveil a super-luxury SUV called the Bentayga. But apparently demand is already outstripping supply -- even though the Bentayga hasn't yet been shown.

Bentley Chairman Wolfgang Durheimer told Business Insiderthat the company will build 3,600 Bentaygas in the first year of production. He said demand already extends far beyond the United States.

This is about more than just jumping into a hot market. For Rolls, a tiny automaker that sold just 4,063 cars last year (a record, by the way), an SUV model offers some diversification, a bit of insurance against a falloff in sales of sedans.

SUV sales can help a small brand get through economic downturnsThat's why Porsche originally developed its Cayenne, after all -- as a hedge against the steep ups-and-downs of its core sports car business. Premium sports cars tend to sell very well during good economic times, but are the first purchase eliminated from many buyers' lists when the economy turns down and it's time to cut spending.

SUV sales have proven a little more resilient. Even though Rolls-Royce is now owned by deep-pocketed BMW, such resilience surely has some appeal.

But mostly, this new Rolls -- which is currently called "Project Cullinan" -- will be a ticket to fat profits for Rolls and BMW for as long as this super-luxury-SUV boom lasts.